I've been doing some reading on BootHole to help understand our attack surface and see everything talking about GRUB2, but nothing about GRUB "Legacy" or GRUB1. Wondering if it has tested against this older version of the bootloader. Older distros (RHEL5 & 6) used GRUB1 and am just curious if they have been proven unaffected by BootHole. I can't be the only one thinking this, but haven't been able to find anyone talking about it.
The original article implies that it is not affected.
In this document, all references to GRUB are intended to refer to GRUB2, which was a complete rewrite from the previous version commonly referred to as “GRUB Legacy.”